In the making of hollow blown articles such as containers from plastic material, it has heretofore been suggested that labels be held in the mold sections by vacuum so that when the parison is blown outwardly into conformity with the cavity, the label becomes adhered or bonded to the article.
In one type of apparatus, commonly known as an injection-blow apparatus, parisons in the form of tubes are extruded from an extruder into a neck mold of a head. The head includes label handling vacuum devices which remove labels from magazines and deposit the labels in an array of cavities of mold sections. One of the problems with such an arrangement is that a magazine is required for each of the label handling vacuum devices.
In another type of apparatus such as shown in U.S. Pat. No. 4,636,166, issued Jan. 13, 1987, intermediate endless vacuum belts are provided and indexed past magazines to pick up successively an array of labels and then the label handling vacuum devices on the head remove the array of labels from the endless belts and deposit the labels in the cavities of the mold sections when the head moves down adjacent the extruder. A problem with such an arrangement is that it is necessary to utilize an intermediate belt with the associated maintenance and alignment problems. More specifically, the labels must be held firmly by the belts and this is sometimes difficult with thin, highly flexible labels such as plastic labels. In addition, the endless vacuum belts require different belts and associated vacuum systems for each label size. A further problem with belts is that they require dynamic seals between the belt and source of vacuum. Also belt friction tends to cause improper indexing such that the labels may not be accurately spaced on the belt so that they are properly positioned with respect to the array of mold sections
Accordingly, among the objectives of the present invention are to provide an in-mold labeling system which is more accurate, simpler, lower in cost and more reliable and which eliminates the use of endless belts.
In accordance with the invention, a vacuum slide is mounted for indexing movement adjacent a source of labels for successively removing labels from a source to provide an array of labels on said slide and label pick up and delivery devices on the head for simultaneously removing the array of labels from the vacuum slide and delivering the array of labels to the array of cavities of the mold sections when the head is moved between the mold sections.